1
|
Gong M, Dong Y, Zhu M, Qin F, Wang T, Shah FU, An R. Cation Chain Length of Nonhalogenated Ionic Liquids Matters in Enhancing SERS of Cytochrome c on Zr-Al-Co-O Nanotube Arrays. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:8886-8896. [PMID: 38622867 DOI: 10.1021/acs.langmuir.4c00067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Surface-enhanced Raman scattering (SERS) is a remarkably powerful analytical technique enabling trace-level detection of biological molecules. The interaction of a probe molecule with the SERS substrate shows important distinctions in the SERS spectra, providing inherent fingerprint information on the probe molecule. Herein, nonhalogenated phosphonium-based ionic liquids (ILs) containing cations with varying chain lengths were used as trace additives to amplify the interaction between the cytochrome c (Cyt c) and Zr-Al-Co-O (ZACO) nanotube arrays, strengthening the SERS signals. An increased enhancement factor (EF) by 2.5-41.2 times compared with the system without ILs was achieved. The improvement of the SERS sensitivity with the introduction of these ILs is strongly dependent on the cation chain length, in which the increasing magnitude of EF is more pronounced in the system with a longer alkyl chain length on the cation. Comparing the interaction forces measured by Cyt c-grafted atomic force microscopy (AFM) probes on ZACO substrates with those predicted by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, the van der Waals forces became increasingly dominant as the chain length of the cations increased, associated with stronger Cyt c-ZACO XDLVO interaction forces. The major contributing component, van der Waals force, stems from the longer cation chains of the IL, which act as a bridge to connect Cyt c and the ZACO substrate, promoting the anchoring of the Cyt c molecules onto the substrate, thereby benefiting SERS enhancement.
Collapse
Affiliation(s)
- Mian Gong
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yihui Dong
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Minghai Zhu
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Fengxiang Qin
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Tianchi Wang
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Faiz Ullah Shah
- Chemistry of Interfaces, Luleå University of Technology, 97187 Luleå, Sweden
| | - Rong An
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| |
Collapse
|
2
|
An R, Wu N, Gao Q, Dong Y, Laaksonen A, Shah FU, Ji X, Fuchs H. Integrative studies of ionic liquid interface layers: bridging experiments, theoretical models and simulations. NANOSCALE HORIZONS 2024; 9:506-535. [PMID: 38356335 DOI: 10.1039/d4nh00007b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Ionic liquids (ILs) are a class of salts existing in the liquid state below 100 °C, possessing low volatility, high thermal stability as well as many highly attractive solvent and electrochemical capabilities, etc., making them highly tunable for a great variety of applications, such as lubricants, electrolytes, and soft functional materials. In many applications, ILs are first either physi- or chemisorbed on a solid surface to successively create more functional materials. The functions of ILs at solid surfaces can differ considerably from those of bulk ILs, mainly due to distinct interfacial layers with tunable structures resulting in new ionic liquid interface layer properties and enhanced performance. Due to an almost infinite number of possible combinations among the cations and anions to form ILs, the diversity of various solid surfaces, as well as different external conditions and stimuli, a detailed molecular-level understanding of their structure-property relationship is of utmost significance for a judicious design of IL-solid interfaces with appropriate properties for task-specific applications. Many experimental techniques, such as atomic force microscopy, surface force apparatus, and so on, have been used for studying the ion structuring of the IL interface layer. Molecular Dynamics simulations have been widely used to investigate the microscopic behavior of the IL interface layer. To interpret and clarify the IL structure and dynamics as well as to predict their properties, it is always beneficial to combine both experiments and simulations as close as possible. In another theoretical model development to bridge the structure and properties of the IL interface layer with performance, thermodynamic prediction & property modeling has been demonstrated as an effective tool to add the properties and function of the studied nanomaterials. Herein, we present recent findings from applying the multiscale triangle "experiment-simulation-thermodynamic modeling" in the studies of ion structuring of ILs in the vicinity of solid surfaces, as well as how it qualitatively and quantitatively correlates to the overall ILs properties, performance, and function. We introduce the most common techniques behind "experiment-simulation-thermodynamic modeling" and how they are applied for studying the IL interface layer structuring, and we highlight the possibilities of the IL interface layer structuring in applications such as lubrication and energy storage.
Collapse
Affiliation(s)
- Rong An
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Nanhua Wu
- Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Qingwei Gao
- College of Environmental and Chemical Engineering, Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power, Shanghai University of Electric Power, Shanghai 200090, China
| | - Yihui Dong
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Aatto Laaksonen
- Energy Engineering, Division of Energy Science, Luleå University of Technology, 97187 Luleå, Sweden.
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
- Center of Advanced Research in Bionanoconjugates and Biopolymers, ''Petru Poni" Institute of Macromolecular Chemistry, Iasi 700469, Romania
- State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Faiz Ullah Shah
- Chemistry of Interfaces, Luleå University of Technology, 97187 Luleå, Sweden
| | - Xiaoyan Ji
- Energy Engineering, Division of Energy Science, Luleå University of Technology, 97187 Luleå, Sweden.
| | - Harald Fuchs
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
- Center for Nanotechnology (CeNTech), Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
| |
Collapse
|
3
|
Li H, Wang J, Warr GG, Atkin R. Effect of Potential on the Nanostructure Dynamics of Ethylammonium Nitrate at a Graphite Electrode. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306011. [PMID: 37806754 DOI: 10.1002/smll.202306011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/20/2023] [Indexed: 10/10/2023]
Abstract
Video-rate atomic force microscopy (AFM) is used to study the near-surface nanostructure dynamics of the ionic liquid ethylammonium nitrate (EAN) at a highly oriented pyrolytic graphite (HOPG) electrode as a function of potential in real-time for the first time. The effects of varying the surface potential and adding 10 wt% water on the nanostructure diffusion coefficient are probed. For both EAN and the 90 wt% EAN-water mixture, disk-like features ≈9 nm in diameter and 1 nm in height form above the Stern layer at all potentials. The nanostructure diffusion coefficient increases with potential (from OCP -0.5 V to OCP +0.5 V) and with added water. Nanostructure dynamics depends on both the magnitude and direction of the potential change. Upon switching the potential from OCP -0.5 V to OCP +0.5 V, a substantial increase in the diffusion coefficients is observed, likely due to the absence of solvophobic interactions between the nitrate (NO3 - ) anions and the ethylammonium (EA+ ) cations in the near-surface region. When the potential is reversed, EA+ is attracted to the Stern layer to replace NO3 - , but its movement is hindered by solvophobic attractions. The outcomes will aid applications, including electrochemical devices, catalysts, and lubricants.
Collapse
Affiliation(s)
- Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Jianan Wang
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
| |
Collapse
|
4
|
Su Y, Wang T, Zhang F, Huang J, Zhu Z, Shah FU, Xu F, An R. Effect of Electrode Surface Chemistry on Ion Structuring of Imidazolium Ionic Liquids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37289976 DOI: 10.1021/acs.langmuir.3c00710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Surface chemistry plays a critical role in the ion structuring of ionic liquids (ILs) at the interfaces of electrodes and controls the overall energy storage performance of the system. Herein, we functionalized the gold (Au) colloid probe of an atomic force microscope with -COOH and -NH2 groups to explore the effect of different surface chemical properties on the ion structuring of an IL. Aided by colloid-probe atomic force microscopy (AFM), the ion structuring of an imidazolium IL, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6], abbreviated as BP hereafter), on the Au electrode surface and the ion response to the change in the surface chemistry are investigated. AFM morphologies, contact angles, and approaching force-distance curves of the BP IL on the functionalized Au surfaces exhibited that the IL forms a more obvious layering structure on the -COOH-terminated Au surface (Au-COOH), while it forms heterogeneous and aggregating droplets on the -NH2 surface (Au-NH2). The formed uniform and aggregation-free ion layers in the vicinity of the Au-COOH surface are due to the π-π+ stacking interaction between the delocalized π+ electrons from the imidazolium ring in the IL [BMIM]+ cation and the localized π electrons from the sp2 carbon on the -COOH group. The in situ observation of nano-friction and torsional resonance frequency at the IL-electrode interfaces further demonstrated the ion structuring of the IL at Au-COOH, which results in a more sensitive electrochemical response associated with a faster capacitive process.
Collapse
Affiliation(s)
- Yiqun Su
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Tiantian Wang
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Fan Zhang
- Department of Engineering and Design, School of Engineering and Information, University of Sussex, Brighton BN1 9RH, U.K
| | - Junsen Huang
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Zhehang Zhu
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Faiz Ullah Shah
- Chemistry of Interfaces, Luleå University of Technology, 97187 Luleå, Sweden
| | - Feng Xu
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Rong An
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094, China
| |
Collapse
|
5
|
Xu J, Cheng J, Yang J, Tao H, Wang S, Lv W, Ma K, Lian C, Liu H. The charge regulation of surfactants on the rock surface in nanoconfinement: A reaction-coupling fluid density functional theory study. Chem Eng Sci 2023. [DOI: 10.1016/j.ces.2023.118718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2023]
|
6
|
Jildani SR, Keshavarzi E. Exploring the electrosorption and surface charge amplification at the ionic liquid/cavity interface: influence of imidazolium alkyl chain length and the size of the spherical cavities of the porous electrode. Electrochim Acta 2023. [DOI: 10.1016/j.electacta.2023.142314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
|
7
|
Shen G, Yang H, Hu Y, Zhang X, Zhou F, Li H, Hong K. Impact of Surface Roughness on Partition and Selectivity of Ionic Liquids Mixture in Porous Electrode. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 13:51. [PMID: 36615961 PMCID: PMC9823643 DOI: 10.3390/nano13010051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/17/2022] [Accepted: 12/18/2022] [Indexed: 06/17/2023]
Abstract
Understanding the influence of surface roughness on the adsorption of ions from an ionic liquids (ILs) mixture is essential for designing supercapacitors. The classical density functional theory (DFT) is applied to investigate the adsorption behavior of ILs mixtures in rough nanopores. The model parameters for each ion are determined by fitting experimental data of pure IL density. The results show that the smaller anions are densely accumulated near the rough surface and are the dominant species at a high positive potential. The exclusion of larger anions is enhanced by roughness at almost all potentials. At negative potential, the surface roughness promotes the adsorption of cations, and the partition coefficient increases with roughness. The partition coefficient of smaller anions is virtually independent of roughness. At positive potential, the surface roughness only promotes the adsorption of smaller anions and raises the partition coefficient. The partition coefficient of smaller anions is far greater than one. The selectivity of smaller anions for rough surfaces is very high and increases with roughness. The surface charge of a more uneven surface is significantly higher (about 30%) at a high potential.
Collapse
|
8
|
Wang T, Li L, Zhang F, Dai Z, Shah FU, Wang W, Xu F, An R. Microstructural probing of phosphonium-based ionic liquids on a gold electrode using colloid probe AFM. Phys Chem Chem Phys 2022; 24:25411-25419. [PMID: 36250344 DOI: 10.1039/d2cp02489f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Atomic force microscopy (AFM) with a gold colloid probe modeled as the electrode surface is employed to directly capture the contact resonance frequency of two phosphonium-based ionic liquids (ILs) containing a common anion [BScB]- and differently lengthened cations ([P6,6,6,14]+ and [P4,4,4,8]+). The comparative interfacial studies are performed by creating IL films on the surface of gold, followed by measuring the wettability, thickness of the films, adhesion forces, surface morphology and AFM-probed contact resonance frequency. In addition, the cyclic voltammetry and impedance spectroscopy measurements of the neat ILs are measured on the surface of the gold electrode. The IL with longer cation alkyl chains exhibits a well-defined thin film on the electrode surface and enhanced the capacitance than the shorter chain IL. The AFM contact resonance frequency and force curves reveal that the longer IL prefers to form stiffer ion layers at the gold electrode surface, suggesting the "…anion-anion-cation-cation…" bilayer structure, in contrast, the shorter-chain IL forms the softer cation-anion alternating structure, i.e., "…anion-cation-anion-cation…".
Collapse
Affiliation(s)
- Tiantian Wang
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing, 210094, China.
| | - Licheng Li
- Innovation Research Center of Lignocellulosic Functional Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China
| | - Fan Zhang
- Department of Engineering and Design, School of Engineering and Information, University of Sussex, Brighton, BN1 9RH, UK
| | - Zhongyang Dai
- High Performance Computing Department, National Supercomputing Center in Shenzhen, Shenzhen, 518055, China
| | - Faiz Ullah Shah
- Chemistry of Interfaces, Luleå University of Technology, 97187, Luleå, Sweden
| | - Wen Wang
- Zhongnong Guoke Planning and Design Co., Ltd, Nanjing, 210014, China
| | - Feng Xu
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing, 210094, China.
| | - Rong An
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing, 210094, China.
| |
Collapse
|
9
|
Manipulating mechanism of the electrokinetic flow of ionic liquids confined in silica nanochannel. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.117913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
10
|
Gan Z, Wang Y, Lu Y, Qin J, Nie Y, He H. Insight into the camel‐to‐bell transition of differential capacitance in ionic liquids‐based supercapacitor. ChemElectroChem 2022. [DOI: 10.1002/celc.202200274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Zhongdong Gan
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
| | - Yanlei Wang
- Institute of Process Engineering Chinese Academy of Sciences Ionic LIquid and Clean Process Beiertiao #1,Zhongguancun, Haidian District 100190 Beijing CHINA
| | - Yumiao Lu
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
| | - Jingyu Qin
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
| | - Yi Nie
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
| | - Hongyan He
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
| |
Collapse
|
11
|
Enhanced oil recovery by sacrificing polyelectrolyte to reduce surfactant adsorption: a classical density functional theory study. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.117957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
12
|
Shen G, Zhang D, Hu Y, Zhang X, Zhou F, Qian Y, Lu X, Ji X. Effect of surface roughness on partition of ionic liquids in nanopores by a perturbed-chain SAFT density functional theory. J Chem Phys 2022; 157:014701. [DOI: 10.1063/5.0098924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, the distribution and partition behavior of ionic liquids (ILs) in nanopores with rough surfaces are investigated by a two-dimensional (2D) classical density functional theory (DFT) model. The model is consistent with the equation of state (EoS) that combines the perturbed-chain statistical associating fluid theory (PC-SAFT) and the mean spherical approximation (MSA) theory for bulk fluid. Its performance is verified by comparing the theoretical predictions to the results from molecular simulations. The fast Fourier transform (FFT) and a hybrid iteration method of Picard iteration and Anderson mixing are used to efficiently obtain the solution of density profile for the sizeable 2D system. The molecular parameters for IL-ions are obtained by fitting to experimental densities of bulk ILs. The model is applied to study the structure and partition of the ILs in nanopores. The results show that the peak of the density profile of counterions near a rough surface is much higher than that near a smooth surface. The adsorption of counterion and removal of coions are enhanced by surface roughness. Thus the nanopore with rough surfaces can store more charge. At low absolute surface potential, the partition coefficient for ions on rough surfaces is lower than that on smooth surfaces. At high absolute surface potential, increasing surface roughness leads to an increase in partition coefficient for counterions and a decrease in partition coefficient for coions.
Collapse
Affiliation(s)
| | - Di Zhang
- Huaiyin Institute of Technology, China
| | - Yongke Hu
- Huaiyin Institute of Technology, China
| | | | - Feng Zhou
- Huaiyin Institute of Technology, China
| | | | - Xiaohua Lu
- Department of Chemical Engineering, Nanjing University of Technology, China
| | | |
Collapse
|
13
|
Wu J. Understanding the Electric Double-Layer Structure, Capacitance, and Charging Dynamics. Chem Rev 2022; 122:10821-10859. [PMID: 35594506 DOI: 10.1021/acs.chemrev.2c00097] [Citation(s) in RCA: 99] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Significant progress has been made in recent years in theoretical modeling of the electric double layer (EDL), a key concept in electrochemistry important for energy storage, electrocatalysis, and multitudes of other technological applications. However, major challenges remain in understanding the microscopic details of the electrochemical interface and charging mechanisms under realistic conditions. This review delves into theoretical methods to describe the equilibrium and dynamic responses of the EDL structure and capacitance for electrochemical systems commonly deployed for capacitive energy storage. Special emphasis is given to recent advances that intend to capture the nonclassical EDL behavior such as oscillatory ion distributions, polarization of nonmetallic electrodes, charge transfer, and various forms of phase transitions in the micropores of electrodes interfacing with an organic electrolyte or ionic liquid. This comprehensive analysis highlights theoretical insights into predictable relationships between materials characteristics and electrochemical performance and offers a perspective on opportunities for further development toward rational design and optimization of electrochemical systems.
Collapse
Affiliation(s)
- Jianzhong Wu
- Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, United States
| |
Collapse
|
14
|
Cheng J, Tao H, Ma K, Yang J, Lian C, Liu H, Wu J. A Theoretical Model for the Charging Dynamics of Associating Ionic Liquids. FRONTIERS IN CHEMICAL ENGINEERING 2022. [DOI: 10.3389/fceng.2022.852070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Association between cations and anions plays an important role in the interfacial structure of room-temperature ionic liquids (ILs) and their electrochemical performance. Whereas great efforts have been devoted to investigating the association effect on the equilibrium properties of ILs, a molecular-level understanding of the charging dynamics is yet to be established. Here, we propose a theoretical procedure combining reaction kinetics and the modified Poisson-Nernst-Planck (MPNP) equations to study the influences of ionic association on the dynamics of electrical double layer (EDL) in response to an applied voltage. The ionic association introduces a new decay length λS and relaxation time scale τRC=λSL/D, where L is the system size and D is ion diffusivity, that are distinctively different those corresponding to non-associative systems. Analytical expressions have been obtained to reveal the quantitative relations between the dynamic timescales and the association strength.
Collapse
|
15
|
Weitzner SE, Pham TA, Meshot ER. Theory-augmented informatics of ionic liquid electrolytes for co-design with nanoporous electrode materials. NANOSCALE 2022; 14:4922-4928. [PMID: 35302123 DOI: 10.1039/d1nr07515b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ionic liquids possess compelling properties and vast chemical diversity, promising unprecedented performance and tunability for advanced electrochemical applications in catalysis, sensing, and energy storage. However, with broad tunability comes intractable, multidimensional parameter spaces not easily traversed by empirical approaches, limiting both scientific understanding and technological breakthroughs with these novel materials. In this Communication, we propose an extensible figure of merit that co-optimizes key ionic liquid properties, including electrochemical stability window, viscosity, and molecular ion size with respect to pore sizes of nanoporous electrodes typically utilized in electrochemical technologies. We coupled density functional theory (DFT) with informatics to augment physiochemical property databases to screen for high-performance room-temperature ionic liquid (RTIL) candidate compounds. This co-design framework revealed a number of promising RTILs that are underrepresented in the literature and thus warrant future follow-up investigations.
Collapse
Affiliation(s)
- Stephen E Weitzner
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, USA.
| | - Tuan Anh Pham
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, USA.
| | - Eric R Meshot
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, USA.
| |
Collapse
|
16
|
Detailing molecular interactions of ionic liquids with charged SiO2 surfaces: A systematic AFM study. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118506] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
17
|
Kraiwattanawong K. A review on the development of a porous carbon-based as modeling materials for electric double layer capacitors. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2021.103625] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
|
18
|
Verma S, Verma A, Mondal M, Prasad NE, Srivastava J, Singh S, Verma JP, Saha S. Drastic influence of amide functionality and alkyl chain length dependent physical, thermal and structural properties of new pyridinium-amide cation based biodegradable room temperature ionic liquids. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131679] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
19
|
Pitawela N, Shaw SK. Imidazolium Triflate Ionic Liquids' Capacitance-Potential Relationships and Transport Properties Affected by Cation Chain Lengths. ACS MEASUREMENT SCIENCE AU 2021; 1:117-130. [PMID: 36785553 PMCID: PMC9885949 DOI: 10.1021/acsmeasuresciau.1c00015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this paper we report the effects of five imidazolium cations with varying alkyl chain lengths to study the effects of cation size on capacitance versus voltage behavior. The cations include ethyl-, butyl-, hexyl-, octyl-, and decyl-3-methylimidazolium, all paired with a triflate anion. We analyze the capacitance with respect to the cation alkyl chain length qualitatively and quantitatively by analyzing changes in the capacitance-potential curvature shape and magnitude across several standard scanning protocols and electrochemical techniques. Further, three transport properties (viscosity, diffusion coefficient, and electrical conductivity) are experimentally determined and integrated into the outcomes. Ultimately, we find higher viscosities, lower diffusion coefficients, and lower electrical conductivities when the alkyl chain length is increased. Also, capacitance values increase with cation size, except 1-octyl-3-methylimidazolium, which does not follow an otherwise linear trend. This capacitive increase is most pronounced when sweeping the potential in the cathodic direction. These findings challenge the conventional hypothesis that increasing the length of the alkyl chain of imidazolium cations diminishes the capacitance and ionic liquid performance in charge storage.
Collapse
|
20
|
Cats P, Sitlapersad RS, den Otter WK, Thornton AR, van Roij R. Capacitance and Structure of Electric Double Layers: Comparing Brownian Dynamics and Classical Density Functional Theory. J SOLUTION CHEM 2021. [DOI: 10.1007/s10953-021-01090-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractWe present a study of the structure and differential capacitance of electric double layers of aqueous electrolytes. We consider electric double layer capacitors (EDLC) composed of spherical cations and anions in a dielectric continuum confined between a planar cathode and anode. The model system includes steric as well as Coulombic ion-ion and ion-electrode interactions. We compare results of computationally expensive, but “exact” , Brownian Dynamics (BD) simulations with approximate, but cheap, calculations based on classical Density Functional Theory (DFT). Excellent overall agreement is found for a large set of system parameters, including variations in concentration, ionic size- and valency-asymmetries, applied voltages and electrode separation, provided the differences between the canonical ensemble of the BD simulations and the grand-canonical ensemble of DFT are properly taken into account. In particular, a careful distinction is made between the differential capacitance $$C_N$$
C
N
at fixed number of ions and $$C_\mu $$
C
μ
at fixed ionic chemical potential. Furthermore, we derive and exploit their thermodynamic relations. In the future these relations will also be useful for comparing and contrasting experimental data with theories for supercapactitors and other systems. The quantitative agreement between simulation and theory indicates that the presented DFT is capable of accounting accurately for coupled Coulombic and packing effects. Hence it is a promising candidate to cheaply study room temperature ionic liquids at much lower dielectric constants than that of water.
Collapse
|